Shorewall
The Shoreline Firewall, more commonly known as "Shorewall", is a high-level tool for configuring Netfilter.
You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and with the help of the iptables utility, Shorewall configures Netfilter to match your requirements.
Shorewall can be used on a dedicated firewall system, a multi-function gateway/router/server or on a standalone GNU/Linux system. Shorewall does not use Netfilter's ipchains compatibility mode and can thus take advantage of Netfilter's connection state tracking capabilities.
Installation
Install the shorewallAUR or shorewall6AUR package.
Configuration
LOGFILE="systemd" in /etc/shorewall/shorewall.conf for the shorewall show command to work. [1]
These settings are based on the two-interface documentation on the Shorewall web site.
Use some example configuration files that come with the shorewall package
# cp /usr/share/doc/shorewall/Samples/one-interface/* /etc/shorewall/ # If you have a desktop-type system with a single network interface # cp /usr/share/doc/shorewall6/Samples6/one-interface/* /etc/shorewall6/ # If you have a desktop-type system with a single network interface, pkg shorewall6 # cp /usr/share/doc/shorewall/Samples/two-interfaces/* /etc/shorewall/ # If you have a router with two network interfaces # cp /usr/share/doc/shorewall/Samples/three-interfaces/* /etc/shorewall/ # If you have a router with three network interfaces
/etc/shorewall/interfaces
Change the interface settings to match the names used for our Ethernet devices and to allow DHCP traffic on the local network. Edit /etc/shorewall/interfaces
original
net eth0 dhcp,tcpflags,nosmurfs,routefilter,logmartians loc eth1 tcpflags,nosmurfs,routefilter,logmartians
new
net wan dhcp,tcpflags,nosmurfs,routefilter,logmartians loc lan dhcp,tcpflags,nosmurfs,routefilter,logmartians
/etc/shorewall/policy
Change the policy file to allow the router (this machine) to access the Internet. Edit /etc/shorewall/policy
original
############################################################################### #SOURCE DEST POLICY LOG LEVEL LIMIT:BURST loc net ACCEPT net all DROP info # THE FOLLOWING POLICY MUST BE LAST all all REJECT info
new
############################################################################### #SOURCE DEST POLICY LOG LEVEL LIMIT:BURST $FW net ACCEPT loc net ACCEPT net all DROP info # THE FOLLOWING POLICY MUST BE LAST all all REJECT info
/etc/shorewall/rules
DNS look-ups are handled (actually forwarded) by dnsmasq, so Shorewall needs to allow those connections. Add these lines to /etc/shorewall/rules
# Accept DNS connections from the local network to the firewall # DNS(ACCEPT) loc $FW
/etc/shorewall/masq
As of version 5.0.14, /etc/shorewall/masq has been deprecated in favor of /etc/shorewall/snat. Add the following line to /etc/shorewall/snat instead of modifying masq.
MASQUERADE 192.168.1.0/24 eth0
Change the network interface to the one connected to your external (WAN) network and change the IP to the one used in your local network.
eth0 192.168.1.0/24
SSH
OPTIONAL: You can add these lines to /etc/shorewall/rules if you want to be able to SSH into the router from computers on the Internet
# Accept SSH connections from the internet for administration # SSH(ACCEPT) net $FW TCP <SSH port used>
Port forwarding (DNAT)
- /etc/shorewall/rules : here is an example for a webserver on our LAN with IP 10.0.0.85. You can reach it on port 5000 of our "external" IP.
DNAT net loc:10.0.0.85:80 tcp 5000
/etc/shorewall/stoppedrules
If you have a network name other than eth1 for the network interface in /etc/shorewall/interfaces, you need to update stoppedrules with the correct name.
/etc/shorewall/shorewall.conf
When you are finished making above changes, enable shorewall by a change in its configuration file /etc/shorewall/shorewall.conf:
original
STARTUP_ENABLED=No
new
STARTUP_ENABLED=Yes
See man page for more info.
Start
Start/enable shorewall.service.
Traffic shaping
Read Shorewall's Traffic Shaping/Control guide.
Here is a configuration as an example:
- /etc/shorewall/tcdevices : here is where you define the interface you want to have shaped and its rates. I have got a ADSL connection with a 4MBit down/256KBit up profile.
ppp0 4mbit 256kbit
- /etc/shorewall/tcclasses : here you define the minimum (rate) and maximum (ceil) throughput per class. You will assign each one to a type of traffic to shape.
# interactive traffic (ssh) ppp0 1 full full 0 # online gaming ppp0 2 full/2 full 5 # http ppp0 3 full/4 full 10 # rest ppp0 4 full/6 full 15 default
- /etc/shorewall/tcrules : this file contains the types of traffic and the class it belongs to.
1 0.0.0.0/0 0.0.0.0/0 tcp ssh 2 0.0.0.0/0 0.0.0.0/0 udp 27000:28000 3 0.0.0.0/0 0.0.0.0/0 tcp http 3 0.0.0.0/0 0.0.0.0/0 tcp https
I have split it up my traffic in 4 groups:
- interactive traffic or ssh: although it takes up almost no bandwidth, it is very annoying if it lags due to leechers on the LAN. This gets the highest priority.
- online gaming: needless to say you cannot play when your ping sucks. ;)
- webtraffic: can be a bit slower
- everything else: every sort of download, they are the cause of the lag anyway.